COPY Rejected Data and Exception Files

it often happened some rows with format issue, data type issue rejected by copy command while try load it by copy command. the query return succeed but some of data rejected.

To do troubleshooting

1. save Rejected Data and Exceptions

COPY large_tbl FROM :file1 ON site01,
               :file2 ON site01,
               :file3 ON site02,
               :file4 ON site02
               DELIMITER '|'
               REJECTED DATA :reject_s1 ON site01, :reject_s2 ON site02 
               EXCEPTIONS :except_s1 ON site01, :except_s2 ON site02;

2. check errors in exceptions file, and fix it one by one